Rapeseed poses a threat to wild plants
04/06/2011Bright yellow with an intense aroma: rape fields dominate whole landscapes in April. Their abundance of flowers is so attractive to bumblebees that wild plants are being increasingly neglected by pollinators, as proven by researchers from the University of Würzburg’s Biocenter.
Where rape fields lie like yellow carpets between green meadows, they lure bumblebees and other wild bees away. This is hardly surprising given that the insects can find far more nectar and pollen in these fields with their masses of flowers.
This has consequences for semi-natural habitats: the Cowslip (Primula veris), which is on the red list of endangered species in several German states, produces 20 percent fewer seeds in this environment because it is no longer pollinated so well by bumblebees. Evidence of this can be found when rapeseed covers an area of as little as 15 percent of the surrounding landscape. The scientists have revealed this effect in a huge field study involving 67 areas in the region around Göttingen.
Andrea Holzschuh from the University of Würzburg’s Biocenter believes that this phenomenon poses a further threat to already endangered wild plants that flower at the same time as rapeseed. To make matters worse, “rapeseed cultivation areas have grown continuously in recent years because the plant’s oil-rich seeds are used to produce biodiesel.”
The impact of large rape fields on semi-natural habitats has been studied by Andrea Holzschuh and Ingolf Steffan-Dewenter together with researchers from the University of Göttingen and the Helmholtz Centre for Environmental Research in Leipzig/Halle. Their findings are published in the latest issue of the magazine “Proceedings of the Royal Society B”.
Further research as part of a European project
What influence do fields with masses of flowers have on semi-natural habitats? Andrea Holzschuh will continue to explore this issue – as a participant in the EU project STEP: 20 teams from 16 countries will spend five years examining how global change is endangering bees and their pollinating activity.
The Würzburg team will coordinate the field research in six European countries for this project. The aim here is to uncover further correlations between cultivated areas of flowering plants and semi-natural habitats. The project will study the impact on pollinating insects, on wild plants, and on cultivated plants that are pollinated by insects.
Contact
Dr. Andrea Holzschuh, Department of Zoology III (Animal Ecology and Tropical Biology) at the University of Würzburg, T +49 (0)931 31-82380, andrea.holzschuh@uni-wuerzburg.de
